Novel ring expansion routes are proposed to synthesize 8, 9, 13, 14-disecosteroid and macrolide hormones. The key steps involve acid catalyzed or sigmatropic rearrangements that result in two, four, or five carbon ring expansions. The major emphasis concerns sigmatropic shifts of potassium alkoxides in highly dissociating media. Experiments are also described that probe the mechanisms of the sigmatropic shift process by following the stereochemistry of optically active systems and by generating related diradicals from azo precursors. BIBLIOGRAPHIC REFERENCES: R.W. Thies and R.E. Boesta, "Thermal Rearrangements of trans-1-Trimethylsiloxy-1-vinylcyclotridec-3-ene", J. org. Chem., 41, 1233 (1976). R.W. Thies and H.J. Shih, "A Ring Expansion Route to Benzo Substituted Medium and Large-Ring-Systems. Synthesis of trans-7,8-Benzocyclododeca-5,7-dien-1-one", J. Org. Chem., 42, 280 (1976).